If you’ve ever taken a physics or astronomy class, you’ll definitely enjoy Force Fields. By tapping on the screen, you can introduce a new force field (gravity well). Drag the force field to the bottom left corner of the screen in order to adjust the strength/rotation rate. If you want to delete a force field, drag it to the bottom right. You’re only allowed 5 force fields at a time (otherwise the particles might never return!). In order to add (or remove) particles, click the menu button. You might also want to play around with the speed of the force fields/particles using the slider found at the top left of the screen. This way you’ll more closely see the interactions that are taking place.

A great feature of this app is the large number of customization settings that you can play around with. You can choose whether you’d like you phone’s accelerometer sensors to alter the gravity or whether or not particles can move beyond the screen. You can also adjust the settings for the multiple modes (force fields, particles, rubber band) that are offered in this app. Some of these options include the shape, color, and appearance of the force fields, as well as how particles interact, the strength of their interactions, and how long of a trace they leave.

Lastly, this app works incredibly well as a live wallpaper (although some might run into trouble finding it, for unknown reasons). With the live wallpaper, force fields will appear wherever you touch your screen and will slowly fade out. This way you can play with it whenever you return back to your homescreen!

Pros:

Accurate particle physics and force field simulation

Countless customization settings

Simple, elegant design and interface

Areas for improvement:

Might be fun to have the view locked on a single particle to watch its journey